The present invention relates to the reduction of the pressure of waste, top or blast furnace gases which may flow from a blast furnace into a bin having lock placed operationally ahead of the blast furnace which gases are subsequently decompressed in relation to each other or in a special gas container, the gases are to be discharged into the free atmosphere through noise-attenuating equipment.
Gases are developed in blast furnaces, for example, and they required discharge, for example, every 150 seconds. Depending upon the size of the furnace such a discharge may involve about one thousand four hundred cubic meters. The discharge, of course, poses a particular problem because it contains dust and the relatively large volume involved here entails the development of a considerable amount of dust.
The removal of these blast furnace or top gases develop basically for reasons of internal pressure equalization is theoretically possible in accordance with two principles. The first principle assumes that the gas occurs on a discontinuous and can accordingly be discontinuously discharged into the outer atmosphere. The second principle involves capturing the gas, treating it and using it some practical manner.
German Pat. No. 29 45 045 discloses a method of the first mentioned kind, i.e. a method in which intermittently the gas is discharged through a sound attenuating device and contains a certain amount of dust. Considering the state of the art, one could consider de-dusting equipment of gas-scrubbing device or plant which commensurate with the discontinuous discharge of top gases remove the dust or a considerable portion thereof in a correspondingly matched process. An assumed volume of sixty cubic meter dust containing gas at a rate on the order of 1,400 cubic meter per second a quantity of 80,000 cubic meters per hour would have to be processed. The de-dusting or scrubbing equipment has to accommodate such quantity. In fact, a de-dusting and dust-scrubbing plant would have to be about sixty times as large as would be necessary if continuous operation were possible. It can thus be seen that de-dusting is a very costly procedure, particularly considering the equipment would run idle but still consume energy.
Another method for removing the dust laden top gas resulting from the pressure equalization in the blast furnace is disclosed in German patent application No. 30 26 019. A low pressure stage is provided in a dust precipitator and decompression is provided for in relation to the counterpressure of the top gas network. Also here all dust removal vessels have to be designed to accommodate the instantaneously arriving gas quantity. Therefore, this dust removal and dust scrubbing equipment is likewise very expensive. Moreover, this particular equipment poses another problem because of the high rate of cleaning, i.e. low proportion in dust which the gas has to have and must not exceed upon discharging. Moreover, this so-called closed system requires a partitioning of the dust scrubbing into a precleaning and postcleaning operation. This is necessary in order to be able to feed the pressure equalization top gas from a low pressure state back into an intermediate stage in the top gas network.